1. Field
The present disclosure relates to numismatic assessment of coin quality. More particularly, the present disclosure relates to methods for grade enhancing mint state coins.
2. State of the Art
In 1949, Dr. William H. Sheldon presented a scale for grading coins. The scale, known as the Sheldon Scale has a seventy-point range including a subset of grades for circulated coins and a subset for uncirculated coins. The circulated coin scaling runs from a grade of 1 (poor) to a grade of 59 (choice, about uncirculated with almost all of the original mint luster remaining), and includes grades such as fair (2), about good (3), good (4), very good (8), fine (12), very fine (20), extremely fine (40), about uncirculated (50), as well as other grades in-between. The uncirculated grade scaling (60-70) are for coins which are called “mint state” or “as new” coins. In the Sheldon Scale, the mint state coins are differentiated by eye appeal, luster, wear, scratches, and hairlines. Thus, a mint state 60 may be considered unattractive, dull or have a washed out luster with hairlines, unattractive large areas of scuff-marks with rim nicks, while a mint state 64 might have average luster and strike with small contact marks in groups as well as one or two moderately heavy marks, one or two small patches of hairlines under low magnification, noticeable light scuff marks or defects, and pleasing eye appeal. A mint state 70, on the other hand, is considered a perfect coin with no trace of wear, handling, scratches or contact with other coins and exceptional eye appeal. Other mint grades in the mint grade subset fall between the extremes.
Recently, some numismatists have started providing an enhanced grade to certain mint state coins. For example, U.S. Pat. No. 8,551,889 to Blake discloses providing an eye appeal indicator symbol (+) adjoining a coin's Sheldon whole number grade on a label attached to a clear plastic coin holder in order to enhance the value of the coin by providing an above-average fractional grade condition for the coin. The eye appeal indicator is based on using determining one or more “axial ultimate refractory angles” (AURAs) of a coin that effectively measure the maximum surface reflectivity of the coin.
While enhanced grades based on eye appeal may be used as a mechanism to attempt to distinguish amongst coins of a single grade, eye appeal, even using surface reflectivity, is an artificial grading. When coins that may be one Sheldon Scale grade apart can sell for a difference on the order of a hundred or even a thousand times the price, an enhanced grading based on an artificial grading mechanism is not particularly desirable.